In order to seal liquid lubricant within a bearing housing through which a rotary shaft is mounted, a seal contact face that engages a runner on the shaft is often used. The runner-to-seal gap is maintained within a controlled range to minimize leakage while generating minimal frictional resistance to rotation.
Friction generates heat which is dissipated by bathing the runner in a flow of liquid lubricant. Cooled lubricant flows into the bearing housing from a heat exchanger and is distributed through various channels and ejected through jets toward sources of heat to cool and lubricate moving parts.
Since the runner is made of metal, the temperature of the runner during operation results in thermally induced expansion and contraction. Therefore to control the runner-to-seal gap, control and regulation of the temperature of the runner is required. The use of oil jets to spray cooled oil on the runner is a conventional manner to maintain runner temperature in a controlled range.